In the casting machine, processed goods of various heat-resistant materials are used as lining materials for a teeming box, a trough and a retaining furnace for transferring, supplying and retaining the molten metal as described above, or as attached members such as a float, a spout, a hot-top ring and a transition plate. Above all, heat-resistant materials in which calcium silicate matter is reinforced with carbon fibers have been widely used because of good heat resistance, high strength although lightweight and further excellent processability (for example, see patent document 1 and patent document 2).
Patent Document 1: Japanese Patent No. 1577427
Patent Document 2: Japanese Patent No. 1638119
On the other hand, also in mobile equipment such as digital cameras, digital video cameras, mobile phones and notebook personal computers, or heavy loads such as automobiles, frames and case bodies tend to be formed by magnesium alloys for weight saving. However, magnesium or a magnesium-containing alloy is very high in activity, and extremely strong in the function of corroding a material that comes into contact with a molten metal thereof. Accordingly, conventional parts comprising calcium silicate matter or an alumina-silica-based material have the problem that only several uses, or only one use in some cases, force them to be exchanged.
In order to enhance corrosion resistance, it has been tried to apply heat-resistant coating materials. However, the existing heat-resistant coating materials are less effective in improving corrosion resistance against the molten metal of magnesium or the magnesium-containing alloy. Further, due to stress applied to a coated portion by the movement of the molten metal and the difference from a base material in the coefficient of thermal expansion, there has also been a problem that the coated portion is separated to entirely lose its effect.